1. Field of the Invention
The present invention relates to socket connectors, especially to a socket connector with anti-distortion functions used for testing Integrated Circuit chips (hereinafter simple for IC chip).
2. Description of Related Art
A socket connector is widely used for IC chip test. A conventional socket connector comprises a base, a movable plate mounted on the base and a plurality of actuators for actuating the movable plate to move relative to the base. The movable plate is movable between a rest position and an operating position. Such socket connectors are disclosed in U.S. Pat. No. 5,186,642 and No. 5,690,281.
Referring to FIG. 3, a conventional socket connector 9 used for IC chip tests comprises a squared flat base 90, a movable plate 91 mounted on the base 90 and movable relative to the base 90, a cover 92, a plurality of springs 96, an auxiliary member 93 and a pair of actuators 95.
The movable plate 91 is a squared plan plate with a squared central portion cut away. The movable plate 91 comprises a plurality of first receiving holes 911 arranged in lines around the squared central portion for receiving pins of the IC chip. A pair of guiding portions 914 is formed at corner portions of a rear side of the movable plate 91. Each guiding portion 914 defines a first engaging hole 916.
The base 90 is a flat and plan plate, and defines a squared cutout at a central portion corresponding to the squared central portion of the movable plate 91. A plurality of second receiving holes 901 is defined through the base 90 corresponding to the first receiving holes 911. A pair of placing portions 903 is formed at opposite lateral sides adjacent to the front side. Four third receiving boles 9012 are defined at corner portions of the base 90.
The cover 92 is a frame and defines an opening 921 at a central portion thereof, thus the first receiving holes 911 of the movable plate 91 are upwardly exposed. A plurality of forth receiving holes (not shown) corresponding to the third receiving holes 9012 of the base 90 is defined on a lower surface of corner portions of the cover 92. A pair of positioning holes 924 is defines at each lateral side of the cover 92.
In assembly, the movable plate 91 are mounted on the base 90, with the first receiving holes 901 corresponding to the second receiving holes 911. The auxiliary member 93 is fixed with the cover 92 through fastening with the positioning holes 924. The actuators 95 are assembled with the corresponding auxiliary member 93 and respectively engaged with the first engaging hole 916 of the movable plate 91 and the placing portion 903 of the base 90. Four springs 96 are received in the third receiving holes 9012 and the forth receiving holes. In operation, an external force is exerted on the cover 92 end the cover 92 is pressed downwardly. The movable plate 91 is actuated from the rest position to the operating position. Because of reserve forces of the springs 96 exerted on corner portions of the cover 92, the cover 92 is easily distorted, which may lead to unreliable contact of the IC chip and the movable plate 91.
Hence, an improved socket connector is required to overcome the disadvantages of the prior art.